The hourly weather conditions on April 5.

Let me check the weather forecast in Japan for you. On April 5, it rained all over Japan except Hokkaido. The highest temperature in Hokkaido is 9 degrees, and the lowest temperature is 2 degrees. The highest temperature in other areas is about 16 degrees, and the lowest is 10 degrees. Okinawa is higher. The rain stopped on April 6th, and the temperature was similar to that on April 5th. The highest temperature in kanto region 18 degrees. It seems that you can't wear too little. I think a sweater and a windbreaker are enough. I can't see it for the time being after the 7 th. But it will be a little hotter soon, and the feeling similar to China Jiangnan will be a little colder sooner or later.